The present invention relates generally to specialty tools, and in particular, to an extraction tool for extracting a glow plug from an engine.
A glow plug is a device that helps some diesel engines start when the engine is cold. Typically, a lower portion of the glow plug extends through a glow plug hole in the engine block, and terminates in a cylinder chamber. During ignition, the lower portion of the glow plug heats the air in the cylinder chamber and helps to ignite the fuel. However, the tolerance between the lower portion of the glow plug and the glow plug hole is usually very small. Further, the repeated heating cycles experienced by the lower portion of the glow plug may cause the lower portion to warp and/or expand over time. As such, extracting the warped glow plug back through the glow plug hole often proves to be a difficult task that can require substantial amounts of force. This force, however, can also cause the glow plug to break during its removal, thereby necessitating the disassembly of certain parts of the engine to remove the glow plug pieces. Therefore, what is needed is a specialty tool that facilitates the removal of the used glow plugs from the engine.
A tool for extracting a glow plug includes an externally threaded shaft, an internally threaded sleeve that engages the externally threaded shaft, and a fixed cavity formed in one end of the externally threaded shaft. The cavity has a side entry to permit the insertion of the glow plug into the cavity in a direction normal to the shaft, and a pair of opposing shoulders integrally formed in opposing sidewalls of the cavity. The opposing shoulders engage the glow plug, and transfer a pulling force to the glow plug during extraction.